In general, an internal combustion engine including oil jets that supply oil to pistons is known. Such an internal combustion engine is disclosed in Japanese Patent No. 4599785, for example.
In Japanese Patent No. 4599785, there is disclosed an internal combustion engine in which a main oil gallery and a sub oil gallery through which oil (lubricating oil) circulates are formed in a cylinder block. In this internal combustion engine described in Japanese Patent No. 4599785, a solenoid valve is provided between the main oil gallery and the sub oil gallery, and the sub oil gallery is connected with oil jets. The oil jets have a function of squirting oil (lubricating oil) for cooling to the back sides of pistons connected with con rods. Opening and closing of the solenoid valve are controlled on the basis of a command from an ECU (electronic control unit) during operation of the internal combustion engine so that in the open state of the solenoid valve, the oil of the main oil gallery is drawn into the sub oil gallery and is squirted from the oil jets. Thus, the temperature of the pistons reciprocating in a cylinder is controlled.